On 01/11/2013 05:13 AM, Daniel P. Berrange wrote:
From: "Daniel P. Berrange" <berrange@redhat.com>
A great many virObject instances require a mutex, so introduce a convenient class for this which provides a mutex. This avoids repeating the tedious init/destroy code --- src/libvirt_private.syms | 4 +++ src/util/virobject.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++-- src/util/virobject.h | 20 +++++++++++ 3 files changed, 109 insertions(+), 2 deletions(-)
+void *virObjectLockableNew(virClassPtr klass) +{ + virObjectLockablePtr obj; + + if (!virClassIsDerivedFrom(klass, virClassForObjectLockable())) { + virReportInvalidArg(klass, + _("Class %s must derive from virObjectLockable"), + virClassName(klass)); + return NULL; + } + + if (!(obj = virObjectNew(klass))) + return NULL; + + if (virMutexInit(&obj->lock) < 0) { + virReportSystemError(VIR_ERR_INTERNAL_ERROR, "%s", + _("Unable to initialize mutex")); + virObjectUnref(obj); + return NULL; + }
This creates the new object locked...
+ + return obj; +} + + +static void virObjectLockableDispose(void *anyobj) +{ + virObjectLockablePtr obj = anyobj; + + virMutexDestroy(&obj->lock);
...but this doesn't unlock anything. You may want to document that the user is required to unlock the object before losing the last reference.
+ * virObjectLock: + * @anyobj: any instance of virObjectLockablePtr + * + * Acquire a lock on @anyobj. The lock must be + * released by virObjectUnlock. + */ +void virObjectLock(void *anyobj) +{ + virObjectLockablePtr obj = anyobj;
Is it worth a sanity check that anyobj is actually an object of the right class, before we blindly dereference something wrong due to a coding error?
+void virObjectUnlock(void *anyobj) +{ + virObjectLockablePtr obj = anyobj; +
And again, would a sanity check help? -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org